Walking beam conveyor



Jan. 29, 1963 P. P. RUPPE WALKING BEAM CONVEYOR 4 Sheets-Sheet 1Original Filed Feb. 9, 1959 IN VEN TOR.

P570? 2 RUPPA m of b Arron/vim:

Jan. 29, 1963 P. P. RUPPE 3,075,635

WALKING BEAM CONVEYOR Original Filed Feb. 9, 1959 4 Sheets-Sheet 2 TEE-S J44 6'86 4 44 a if /Q) \llH 4 1 YINVENTOR. P4727? P. lyk/ppi BY Jan.29, 1963 P. P. RUPPE WALKING BEAM CONVEYOR 4 Sheets-Sheet 3 OriginalFiled Feb. 9, 1959 zaa'k INVENTOR. Pars/r P. ROPP 47' TOR/V5719 Jan. 29,1963 Original Filed Feb. 9,

P. P. RUPPE WALKING BEAM CONVEYOR 4 Sheets-Sheet 4 & K

INVENTOR.

ATTORNEYS United States Patent Oiilice 3&15535 Patented Jan. 29, 1%633,975,635 WALKENG BEAM C(DNVEYGR Peter 1?. Ruppe, 20 Hampton Road,Grosse Pointe, l'viich. @riginai application Feb. 9, 195?, Ser. No.792,034, new Patent No. 3,093,615, dated Oct. 10, 1961. Divided and thisapplication May 18, 1961, Ser. No. 111,069 6 Claims. (ill. 198-21*) Thisinvention relates to apparatus for conveying articles. This applicationis a division of application Serial Number 792,034, filed February 9,1959, now US. Patent No. 3,003,615.

In general the articles to be conveyed are moved stepby-step along anarticle-supporting surface, being lifted slightly off the surface duringthe movement and replaced on the surface during the pauses in themovement. To accomplish this, an article carrier reciprocateslongitudinally or" the supporting surface, being elevated relativethereto during movement in one direction to lift articles off thesurface and shift them longitudinally thereof, and being loweredrelative to the supporting surface to replace the articles thereonduring movement in the opposite direction.

The apparatus comprising the above-described general arrangement, and ashereinafter disclosed, includes a runway or the like along which thearticles to be conveyed are moved, with an article carrier or walkingbeam so disposed relative to the article-supporting surface of therunway that it will move from a position beneath such surface to anelevated position above such surface. Mechanism for reciprocating thebeam longitudinally of the runway and for raising and lowering the beamserves to shift the beam, while elevated, in one direction and retractthe beam, while lowered, in the opposite direction, with articlesresting on the runway being raised therefrom and shifted therealongduring the elevated shifting of the walking beam.

The articles are raised off the supporting surface of the runway onlysufficiently to clear such surface and prevent dragging of the articlesas they are moved along the runway. In the embodiment herein disclosedthe elevation of the Walking beam to convey articles is accomplished bythe cooperation of cam-like surfaces and cam followers, being effectiveto raise the beam to an article-supporting position as they traverse thecam surfaces during movement of the beam in one direction along therunway but being ineffective to raise the beam to an article-supportingposition during movement thereof in the opposite direction even thoughthe followers ride over the cam surfaces.

The subject matter of this application to which the claims are directedis shown in FIG. 9.

Other objects, advantages, and meritorious features will more fullyappear from the specification, claims, and accompanying drawing,wherein:

PEG. 1 is a plan view of a conveyor system embodying my invention;

F G. 2 is a cross sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a cross sectional view taken on the line 3-3 of FIG. 2 andshowing the article carrier in the elevated position;

FIG. 4 is a cross sectional view taken on the line 3-3 of FIG. 2 andshowing the article carrier in the lowered position;

FIG. 5 is a cross sectional view taken on the line 5-5 of FIG. 3 andshowing the cams for elevating the articlev carrier and the mechanismfor actuating the cams between operative and inoperative positions, andwith the cams in the position to elevate the article carrier;

FIG. 6 is a cross sectional view taken on the line 55 of FIG. 3 andshowing the mechanism disclosed in FIG. 5 but with the cams shifted toan inoperative position;

FIG. 7 is a cross sectional view taken on the line 7-7 of FIG. 2;

FIG. 8 is a modification of the cam arrangement shown in FIGS. 5 and 6to allow reversing of the conveyor system so that articles may beconveyed in opposite directions; and

FIG. 9 is a modified form of the means for elevating the article carrierand showing cam followers which are operative to elevate the articlecarrier during its movement in only one direction longitudinally of thearticle-supporting runway.

As shown in FIG. 1 the apparatus embodying the invention includes a pairof cooperating article supports, generally indicated at 20 and 22,having co-adjacent longitudinally extending article-supporting surfacesalternatively operative to support articles thereupon. Mechanismincluding means 24 is coupled with these supports to shift themlongitudinally relative to each other. Such mechanism also includesmeans 26 adjacent opposite ends of the supports for raising one of thesupports relative to the other during longitudinal shifting of thesupports in one direction and lowering the raised support duringlongitudinal shifting in the opposite direction, whereby articles Aresting on support 24) are raised therefrom by support 22 and shiftedalong support Ztl and lowered thereupon, with support 22 while loweredbeing returned to its starting position for repetition of the cycle,with the articles being thereby conveyed along support 20 in astep-by-step fashion. It will be apparent that a longitudinal end-to-endsuccession of the conveyor mechanism shown in FIGS. 1 and 2 might beprovided whereby articles could be conveyed a substantial distance.

More specifically, the support 2i serves as a runway or the like alongwhich the articles to be conveyed are moved in the aforementionedstep-by-step fashion. The runway, which may be supported in anyconvenient manner, not shown, includes a shallow frame (see FlGS. 1-5)having longitudinally extending inwardly opening channel-shaped sideframe members 28 and 3% extending the length of the runway and held inspaced parallel relation by floor means in the form of plates 32, 34 and36 extending transversely therebetween and secured thereto in anysuitable rigid fashion. The upper surfaces of floor plates 32 and 36provide, as ereinafter appears, article carrier-supporting surfaces ortrackways supporting the article carrier for movement longitudinally ofthe runway. The upper flanges 33 and 4? of the side channels serve asarticle-supporting surfaces for the runway upon which the bottoms of thearticles to be conveyed intermittently rest during movement along therunway. To complete the runway and conceal much of the operatingmechanism of the conveyor, a wide article-supporting plate 42, whoselongitudinal edges 44 are downturned and spaced inwardly fromcomplementary edges 46 and d8 of flanges 3E and 4th to provide slotsthrough which project the hereinafter-described walking beam, extendslongitudinally of the frame along the center portion thereof and issupported coplanar with flanges 33 and 4% by angle brackets 46, 4%, 5tand 52, as shown in FIGS. 2 and 3. it is now apparent that except forthe walking beam slots in the upper surface of the runway, the runway issubstantially completely enclosed at the sides and top. As such, itgives a finished appearance and prevents tampering with the mechanismhoused therewithin, as well as preventing iniury to personnel workingadjacent the conveyor. In addition, this unitary construction allowsinstallation of the conveyor as a unit in any desired location withoutthe necessity of providing additional pulleys, shafts, guideways, etc.,frequently associated with many other forms of conveyors.

Extending periodically upwardly out of the slots formed between theedges 44 of center plate 42 and the flanges 3S and are thearticle-lifting and conveying means, specifically the article carriers54 and 56 which are the article-engaging portions of the walking beammechanism. These supports are a pair of parallel bars or narrowvertically arranged plates which extend longitudinally throughoutsubstantially the entire length of the runway, terminating short of theends thereof as shown in FIG. 1. These carriers are disposed within thewalking beam slots and are guided for longitudinal movement by thedownturned edges 44, as and 48, which form the sides of the slots. Theupper edges or surfaces of these carriers serve as article-liftingsurfaces for articles resting upon the article-supporting surfaces ofthe runway.

The carriers are supported for reciprocation longitudin'ally of therunway by roller means. More specifically they are supported upon a pairof fixed axles 58 and 60, as best shown in FIGS. 1, 3 and 5, with wheels62 rotatably mounted on opposite ends of the axles. These wheels, whichmay also be considered somewhat as cam followers, roll upon the uppersurfaces of the floor plates 32 and 36. To effect the longitudinalshifting of the walk ing beam as well as its raising and lowering, themeans 24 and 26 heretofore mentioned is disposed within the runwayenclosure. Means 24 includes, in the illustrative embodiment shown, afluid pressure cylinder 64 pivotally connected as at 66 to the floorplate 34 and provided with a cooperating piston 68 pivotally connectedto a bracket 7%) extending between and secured to the supports 54 and S6of the walking beam. By alternate pressurization of opposite ends ofcylinder 64, such as by an electrically operated fluid pressure valve65, under the control of limit switches 65a and 65b actuated by fingers87a and $612 similar to fingers 816 and 87 hereinafter mentioned, thevalve being connected to a source of fluid pressure, the piston 68 willcause the walking beam to reciprocate longitudinally of the runway.

As the walking beam reciprocates, means 26 serves to raise and lower itrelative to the article-supporting surface of the runway between theposition shown in FIG. 4 wherein the upper surfaces of supports 56 and58 are below the article-supporting surfaces of the runway, and theposition shown in FIG. 3 where the supports are elevated above therunway to lift an article therefrom for movement along the runway spacedthereabove, serves, in effect, to raise and lower the effective heightof the upper surfaces of floor plates 32 and 36, or in other words, theeffective height of the article carrier-supporting surface over whichthe carrier passes during its reciprocation longitudinally of therunway. Means 26 includes four cams, one for each Wheel 62. Three of thecams are shown in FIGS. 2-5 at '72, 74 and 76. The cams are laterallyslidable on their respective floor plates 32 and 36 from operativepositions in which the wheel '62 will -roll over them to raise and lowerthe walking beam, to inoperative positions out of the paths of thewheels.

To effect shifting of the cams, each is carried by an actuating arm,with the arms arranged in pairs for simultaneous actuation. Adescription of the cams '72 and 74, their actuating arms, and othermechanism for operating them at the left-hand end of the conveyor asshown in PEG. 2, will sufiice for the pair of cams, their actuatingarms, and other mechanism for operating them at the right-hand end ofthe conveyor, as both pairs are of similar construction and operation.Referring to FIGS. 4 and 5, it will be noted cams 72 and 74 are secured,in any convenient fashion, to L-shaped arms '78 and 80, each of which ispivotally mounted respectively at 82 and 84 upon the floor plate 32.Because the cams must be operative to raise the walking beam during'itsmovement in one "sli'dably connect the plate to the arm.

chronized with the reciprocation of the beam. To effect thissynchronized movement, alternately operative cam shift fingers 86 and 87are secured, in any convenient fashion, at longitudinally spaced apartpositions along and to one of the article supports 56 to strike thefinger engaging rollers 38 and 90 upstanding respectively from arms 78and 80 to pivot the arms between the positions shown in F168. 5 and 6-.In the latter figure the cams 72 and 74 are in their inoperativepositions.

With the walking beam moving in the direction of arrow C in FIG. 5, thewheels 62 are passing over cams 72 and '74 and the walking beam is inthe elevated position. It will be apparent that the walking beam is heldin the elevated position throughout the length of the high point of thecams. The cams, as shown in FIG. 2, are shaped to have upper surfaceswhich extend lengthwise of the direction of movement of the walking beamwith such upper surfaces having a fiat portion across which the wheels62 will roll and it is during the travel of the wheels across such flatelevated surfaces of the cams that the conveying of articles A iseffected. The length of the fiat elevated surface of the cams need notbe great because, by continued reciprocation of the walking beam, thearticles will be moved in a uniform step-by-step movement along therunway, and the length of the elevated flat portion of the cams willsimply determine the distance the articles are moved between the pausesin the step-by-step movement. As wheels 62 ride down off the cams andreturn to the floor plate 32, see FIG. 5, finger 36 strikes pin rollers88 and he to swing cams 72 and 7dinwardly to the FIG. 6 position. Atthis instant the fluid pressure to cylinder 64- is redirected to enterthe opposite end of the cylinder and the longitudinal movement of thewalking beam is reversed. Because the cams 72 and 74 have been retractedfrom the path of the wheels 62, the 'walking beam retracts withoutelevation. As piston 68 nears the inward end of its stroke and thewheels 62 have passed beyond cams 72 and 7d, cam actuating finger 87strikes the pin rollers 88 and 9t shifting the cams laterally outwardlyback into the path of the wheels. Cylinder 64 at this time is againreversely pressurized and the walking beam reverses the longitudinalmovement. Wheels 62 ride up the cams 72 and 74 elevating the walkingbeam to lift articles resting on the runway and to come therealong andagain set them on the runway as the wheels run down off the cams. Thiscyclic movement repeats itself in rhythmic fashion to move the articlesA along the runway in a 'step-by-step manner.

As thus far described, the conveyor will move articles in only onedirection along the runway. However, in a modified form of the cammechanism shown in FIG. 8, the conveyor may be easily adjusted toreverse the movementof articles thereon. As with the previouslydescribed embodiment, two pairs of cams are provided with the camsmounted on pivoted pairs of arms, one pair being shown at 92 and 94 inFIG. 8 with it being understood that the cam mechanism at the other endof the walking beam is of identical construction except as hereinaftermentioned. Arms 92 and 94 are pivoted upon the floor .plate 36-to 96 and98. A pin roller ran on arm 94 cooperates with a slot 102 in thecompanion arm so that the arms will shift synchronously. An actuatingrod 104 pivotally connected as at 1% to arm Z extends longitudinally ofthe runway just beneath the center plate 42 and is pivotally connectedat its opposite end to an arm, of the other pair of arms, correspondingto arm 92. As thus far described, the cam mechanisms coupled to op-.posite ends of rod 164 are identical and upon actuation of 'the camarms '92'and 94-, the rod 104 will cause corresponding movement of theother pair of arms at'the opposite end of the runway.

Arm 92 is provided with a slidable reversing plate 108 having slotstherein through which bolts 110 and 112 A handle 114 is rigidlyconnected to the plate and projects outwardly through the side of therunway through a slot 116-. Upstanding from the reversing plate are twoarm shifting pins 118 and 126i. Secured in any convenient fashion atlongitudinally spaced-apart points to opposite sides of the carrier 56are two pairs of cooperating cam arm actuating fingers, one pair beingindicated at 122 and 124, and the other pair at 126 and 123. Fingers 122and 124 cooperate with arm shifting pin 120 to effect actuation of camarms 92 and 94 so that articles are conveyed along the runway in thedirection of arrow D while fingers 126 and 12S cooperate with pin 118 tocause the walking beam to move articles along the runway in thedirection of arrow B.

T he operation of the FIG. 8 modification may be visualized fromconsideration of, first, the solid outline position of the arms 92 and 99-, and thereafter a consideration of the phantom outline of the arms.In the solid outline the reversing plate 1% is shown in its slidableposition on the arm 92 so that articles will be shifted in the directionof arrow D. The finger 122 has just struck pin 120 with the supports 56and 54 moving in the direction of arrow D to swing the earns 72 and 74inwardly and out of the path of the wheels 62. Reverse movement ofcarriers 54 and 56 will now occur without elevation thereof. Once thewheels 62 have passed beyond the ends of cams 72 and 74, actuatingfinger 124 will strike pin 12% to swing the arms 92 and 94 outwardly toposition the cams in the path of the wheels 62. Thereafter, uponmovement of the carriers 54 and 56 in the direction of arrow D, thecarriers will be elevated and the articles will be moved along therunway in the direction of arrow B.

To reverse the movement of the articles on the conveyor, and assumingthat the carriers are in the positions shown in FIG. 8, the operatorgrasps handle 114 and through a combined swinging and pushing of handle114- in the direction of and corresponding to the shape of arrow F, heswings the arms 92 and 9d radially outwardly to the phantom outlineposition shown. During this swinging movement and inward pushing ofhandle 11%, the reversing plate 108 is shifted inwardly so that the pins118 and 12*!) assume the phantom outline positions indicated at 118' and12%. It will be noted that the phantom outline position of pin 12% isdisposed inwardly and out of the path of movement of actuating fingers122 and 124, while pin 118 in its phantom outline position 113 is in thepath of movement of fingers 126 and 128.

Assuming that the supports now move in the direction of arrow B, wheels62 will ride up over cams 72 and 74 shown in phantom outline at 72 and74' to elevate the supports and shift the articles in the direction ofarrow E. Near the end of the stroke of the supports, finger 128 willengage pin 118 in its phantom position 118 to swing arms 92 and 94inwardly and through rod 104 to cause corresponding movement of the camarms at the opposite end of the walking beam. Thereupon reverse movementof the supports in the direction of arrow D Will allow the supports toreturn to the positions shown in FIG. 8 without elevation and whenfinger 126 strikes pin 118 in its phantom outline position, the arms 92and-94 will be swung to the phantom outline position to dispose cams 72and 74 at the position 72 and 74. It is now apparent that articles willbe moved along the runway in the direction of arrow E.

Shown in FIG. 9 is a further modification of the in vention. Thismodification overcomes the necessity of laterally shifting the cams outof the path of the wheels 62 in order to prevent elevation of thewalking beam during movement in one direction. In this modification thewheels 62, heretofore mentioned in connection with FIGS. 1-8, instead ofbeing mounted in fixed relation with supports 54 and 56, are connectedthereto by swinging links. The wheels are indicated in two differentpositions, a low-level position at 162 and a high-level position at 162'in FIG. 9. They are mounted in pairs as heretofore described at oppositeends of axles, one of the axles being shown in FIG. 9 at 153. The axlesare connected to the carriers 54 and 56 by pairs of swinging links, oneof which is shown at 164, being pivotally connected to the supports asat 166. The supports are provided with cutouts in the form ofrectangular notches 168 and the axle 158 is capable of swinging aboutits pivotal connection 166 between the position shown in solid outlineat the left in FIG. 9 and the position shown in phantom outline. Theelevating cam 175) over which the wheel 162 rides is provided with theflat upper surface 172 corresponding to the flat surface heretoforementioned in connection with cams '72 and 76. However, cam has differentangles of approach at opposite ends. The approach angle at the left andindicated at 174 is not as steep as the approach angle at the oppositeend indicated at 176. These different approach angles at opposite endsof the cam together with the pivotal connection 166, being disposed moreclosely adjacent the end 178 of notch 176 than it is relative to the end18% of the notch, serve to cause swinging of the wheel axis 158 betweenthe solid and phantom positions.

The cams 170 serve in effect to provide the carrier-supporting surfacesof the floor plates 32 and 36 with a highlevel portion 172 and alow-level portion 123. The notches 168 serve as means limiting thepivotal swinging movement of the wheel links 164.

Assuming that the walking beam has finished its movement in thedirection of arrow F of FIG. 9, and starts its movement in the directionof arrow G, the wheel 16?; will engage the step 182 at the end of cam37d and the resistance to rolling movement offered by the step willcause the link 16 5 to swing from the phantom position shown in FIG. 9to the solid position. As the movement of the walking beam continues inthe direction of arrow G, wheel 262 will ride up over the cam 1'76 anddown the inclined surface 176. During such movement the upper surface184 of the walking beam will be disposed below the artiole-supportingsurface 186 of the runway. However, upon movement of the walking beam inthe direction. of arrow F, the resistance offered wheel 162 by the steepslope 176 of the cam will cause the axle 158 to swing from the solidoutline position to the phantom outline position indicated at 253. Thewalking beam will now be disposed with its supporting surface 134disposed beneath the article-supporting surface 186 of the runway but ata higher elevation than it was in the solid outline position. Continuedmovement of the walking beam in the direction of arrow P will cause thewheel to ride up the inclined surface 1'76 of the cam and onto the fiat172 at which time the surface 184 will be disposed above thearticle-supporting surface 136 of the runway and articles on the runwaywill be lifted therefrom and moved therealong until the wheel 162 ridesdown the slope 174-. Movement of the walking beam in the direction ofarrow G will, as heretofore mentioned, cause the axle to swing from thephantom outline position to that of the solid outline position loweringthe walking beam so that its return movement will be ineffective to movethe articles on the runway.

What is claimed is:

1. An article conveyor comprising, in combination: an article supporthaving a longitudinally extending articlesupporting surface along whicharticles to be conveyed are moved; an elongate article carrier extendinglongitudinally of said supporting surface; a trackway over which thecarrier moves; drive mechanism coupled with the carrier forreciprocating it longitudinally relative to said supporting surface;said trackway having a high surface portion and a low surface portionover which the carrier moves; means secured to the carrier and ridingupon said trackway and over said surface portions and supporting thecarrier for movement on the trackway, said means shiftable with thecarrier during longitudinal shifting thereof and also shiftable relativeto the carrier between high-level and low-level positions such that whendisposed in "the high-level position and riding over the high-levelsurface portion of the trackway the carrier is elevated to dispose itsupper surface above the articlesupported surface of said support'to liftarticles therefrom and move them, and when said means are disposedin thelow-level position and ride over the high-level surface portion'of thetrackway the upper surface of the carrier is disposed'belowthe'article-supporting surface of said support; and means cooperatingwith the first-mentioned means to shift the same to the high-levelposition at one end of the high-level surface portion and shift the sameto the low-level position at the opposite end of the highlevel surfaceportion synchronously withthe-reciprocation of the carrier.

2. An article conveyor comprising, in combination: an, article supporthaving a longitudinally extending articlesupporting surface along whicharticles to be conveyed are-moved; an elongate article carrier extendinglongitudinally of said supporting surface; a trackway over which thecarrier moves; drive mechanism coupled with the carrier forreciprocating it longitudinally relative to said supporting surface;said trackway having a raised portion over which the carrier moves, saidraised portion having inclined surfaces atopposite ends with theinclineat one end being steeper than the incline at the-opposite end;supporting means pivotally connected to the carrier and riding on saidtrackway and supporting the carrier for movement over the trackway; stopmeans limiting the pivotal swing of the supporting means between ahighlevel position elevating the carrier such that its upper surface isabove said article-supporting surface when the supporting means rideover said raised portion of the trackway, and a low-level position inwhich the upper surface of the carrier is below said article-supportingsurface as the supporting means rides over the raised portion of thetrackway; and said steeper inclined surface of such raised portioncooperating with the pivoted supporting means as the carrier moves in adirection causing the supporting means to ride up such incline to pivotthe supporting means from its low-level to its high-level position andwith the less steep incline at the opposite end of such raised portioncooperating with said supporting means to pivot the same to itslow-level position.

3. In a step-by-step article conveyor: an elongate runway surface alongwhich articles are to be conveyed; an article carrying memberreciprocable in the direction of intended article movement along therunway; a member disposed beneath said carrier member; one of saidmembers having a high surface portion and a low surface portion; carriermember supporting means including a lever arm pivotally connected at oneend to the other of said members and provided at the opposite end with aroller for riding over said high and low surface portions with saidleverarm swingable between a first position in which the carrying membersupports articles above the runway surface for travel on the carryingmember as the roller rides over at least one of said surface portions,and a second position in which articles rest on the runway as thecarrying member moves therebeneath in the opposite direction and theroller rides over'said one surface portion; stop means limitingswingable movement of said lever arm between said first and secondpositions; and means cooperable with the carrier supporting means toswing the lever arm from one position to the other at opposite ends ofsaid one surface portion during recipro- 'catory travel of the carriermember.

4. The invention as defined in claim 3 characterized in that the lastmentioned means comprises surfaces, at opposite ends of said one surfaceportion, over which said roller must travel with such surfaces resistingtravel of the roller towards said one surface portion duringreciprocation of the carrier member to cause said lever arm to pivot.

51"111 a conveyor having an elongate runway along which articles areconveyed step-by-step with the articles resting on the runway betweensteps and lifted therefrom and moved th'erealong during the steps,article carrier means disposed beneath and extending in the direction'of conveyance of articles resting on the runway, frame means, one ofsaid means having high-level'and low-level surfaces arranged inalignment in the direction of article conveyance with a high-levelsurface disposed between a pair of low-level surfaces, carrier meanssupporting mechanism extending between and cooperating with the carrierand frame means and including a lever arm pivotally connected to theother of said means and extending angularly toward the said high andlow-level surfaces, bearing means on the lever arm for engaging saidsurfaces, means 'cooperable wtih said 'rnechanism during engagement ofsaid bearing means with the low surfaces to swing the lever arm betweenone angular position such that the carrier means raises articles fromthe runway and conveys them 'therealong as said bearing means engagesthe high level surface during movement of the carrier means in onedirection of "reciprocation, and another angular position such thatarticles rest on the runway as said bearing means engages saidhigh-level surface during movement of the carrier means in the oppositedirection of reciprocation, and stop means for limiting swinga'blemovement of said lever arm between the aforesaid two angular positions.

6. In a conveyor having an elongate runway'along which articles areconveyed step-'by-step with the articles resting -on tl1e runway betweensteps and lifted therefrom and moved'therealong during the steps,article carrier means disposed beneath'and extending in the direction ofconveyance of articles resting on the runwa frame means, one of saidmeans having relativeiy fixed high level and low-level surfaces arrangedin alignment in the direction of article conveyance, mechanism extendingbetween the iframe means and carrier means and supporting the carrierfor reciprocating movement, said mechanism including a member'movably'connected to one of said means and'iprovided with a bearingdevice engaging said surfaces, means cooperable with said mechanismduring engagement of the bearing device with'said'low surface portion toincrease the'eifective length of the movable member to raise the carriermeans prior to the bearing device engaging the high-level surface duringmovement of the carrier means in one direction and shortenthe effectivelength of said movable member prior to the bearing device engaging thehigh-level surface during movement of the "carrier *means in theopposite direction, and limiting means cooperable with said movablemember to limit its movement between said greater and shorter effectivelengths.

No references cited.

1. AN ARTICLE CONVEYOR COMPRISING, IN COMBINATION: AN ARTICLE SUPPORTHAVING A LONGITUDINALLY EXTENDING ARTICLESUPPORTING SURFACE ALONG WHICHARTICLES TO BE CONVEYED ARE MOVED; AN ELONGATE ARTICLE CARRIER EXTENDINGLONGITUDINALLY OF SAID SUPPORTING SURFACE; A TRACKWAY OVER WHICH THECARRIER MOVES; DRIVE MECHANISM COUPLED WITH THE CARRIER FORRECIPROCATING IT LONGITUDINALLY RELATIVE TO SAID SUPPORTING SURFACE;SAID TRACKWAY HAVING A HIGH SURFACE PORTION AND A LOW SURFACE PORTIONOVER WHICH THE CARRIER MOVES; MEANS SECURED TO THE CARRIER AND RIDINGUPON SAID TRACKWAY AND OVER SAID SURFACE PORTIONS AND SUPPORTING THECARRIER FOR MOVEMENT ON THE TRACKWAY, SAID MEANS SHIFTABLE WITH THECARRIER DURING LONGITUDINAL SHIFTING THEREOF AND ALSO SHIFTABLE RELATIVETO THE CARRIER BETWEEN HIGH-LEVEL AND LOW-LEVEL POSITIONS SUCH THAT WHENDISPOSED IN THE HIGH-LEVEL POSITION AND RIDING OVER THE HIGH-LEVELSURFACE PORTION OF THE TRACKWAY THE CARRIER IS ELEVATED TO DISPOSE ITSUPPER SURFACE ABOVE THE ARTICLESUPPORTED SURFACE OF SAID SUPPORT TO LIFTARTICLES THEREFROM AND MOVE THEM, AND WHEN SAID MEANS ARE DISPOSED INTHE LOW-LEVEL POSITION AND RIDE OVER THE HIGH-LEVEL SURFACE PORTION OFTHE TRACKWAY THE UPPER SURFACE OF THE CARRIER IS DISPOSED BELOW THEARTICLE-SUPPORTING SURFACE OF SAID SUPPORT; AND MEANS COOPERATING WITHTHE FIRST-MENTIONED MEANS TO SHIFT THE SAME TO THE HIGH-LEVEL POSITIONAT ONE END OF THE HIGH-LEVEL SURFACE PORTION AND SHIFT THE SAME TO THELOW-LEVEL POSITION AT THE OPPOSITE END OF THE HIGHLEVEL SURFACE PORTIONSYNCHRONOUSLY WITH THE RECIPROCATION OF THE CARRIER.